1. Field of the Invention
The present invention relates to a slide member formed thereon a coat layer made of a dry coat lubricant to increase abrasion resistance and to decrease frictional coefficient.
2. Description of the Related Art
Various slide members sliding relative to a mate member with contacted therewith have been known. In such slide members, a coat layer (film) made of resin binder, hard particles and a solid lubricant etc. is formed on surface of a base (mother) member. The coat layer increases the abrasion resistance and decreases the friction coefficient of the slide member (refer to Patent documents 1 to 3 listed below).
When these coat layers described in the patent documents 1 to 3 are formed by one coat, there may be cases adherence of the coat layer to the base member is not sufficient. If the adherence is insufficient, the coat layer may be peeled off from the base member surface in relatively short time period, depending on using condition of the slide member. Thus, duration of increased abrasion resistance and decreaced friction coefficient resulted from the coat layer is hindered. In view of this, a primer for securing the adherence is coated on the base member in advance, as occasion demands. Then, the coat layer is coated the primer on an upper layer thereof. As a result, man-hour and cost for the coating increases.
When an aluminum alloy and a magnesium alloy poor in slide property are used for the base member, burn-in (seizing) or galling may occur if using condition is strict. Due to large friction coefficient of the aluminum alloy and magnesium alloy, following two manners have been adopted when these materials are used for the base member. The first manner is to plate nickel, tin or denature cover film treatment on the base member surface. The second manner is to cover or coat the base member surface by the dry coat layer (film) made by mixing some kinds of solid lubricants with the thermosetting resin. In any manners, treating cost increases.
Complex plating in which the solid lubricant is dispersed, is effective to prevent occurrence of seizing. However, the plated layer made of the complex plate has large friction coefficient and is expensive. In addition, making the plated layer thicker needs additional finishing process, which hinders adaptation of the plated layer to the aluminum alloy.
A composition in which some kinds of solid lubricants are mixed with the conventional thermosetting resin is used as the coat layer. However, due to low adherence, the coat layer is apt to be peeled off from the base member, resulting in earlier abrasion of the slide member.
For overcoming disadvantage of the above slide members, Applicant of this application has developed the dry coat lubricant (refer to Patent document 4 below) which has the low friction coefficient and high abrasion resistance. This dry coat lubricant increases adherence to the base member, in addition to the above mentioned advantage, and can make the coat layer thicker by one coating, regardless of kind of the base member. However, for further increasing the slide property, the slide member in which the friction quality such as the friction coefficient, abrasion resistance, and seizing preventing property to the base member are further improved, has been required.
[Patent document 1] Japanese Patent Laid-open No. 10-37962
[Patent document 2] Japanese Patent Laid-open No. 7-97517
[Patent document 3] Japanese Patent Laid-open No. 6-279708
[Patent document 4] Japanese Patent Application No. 2002-16023